19 April

65 – The freedman Milichus betrayed Piso’s plot to kill the Emperor Nero and all the conspirators were arrested.
1012 – Martyrdom of Ælfheah in Greenwich, London.
1529 – The Second Diet of Speyer bans Lutheranism; a group of rulers (German: Fürst) and independent cities (German: Reichsstadt) protests the reinstatement of the Edict of Worms, beginning the Protestant Reformation.
1677 – The French army captures the town of Cambrai held by Spanish troops.
1713 – With no living male heirs, Charles VI, Holy Roman Emperor, issues the Pragmatic Sanction of 1713 to ensure that Habsburg lands and the Austrian throne would be inherited by his daughter, Maria Theresa of Austria (not actually born until 1717).
1770 – Captain James Cook sights the eastern coast of what is now Australia.
1770 – Marie Antoinette marries Louis XVI in a proxy wedding.
1775 – American Revolutionary War: The war begins with an American victory in Concord during the battles of Lexington and Concord.
1782 – John Adams secures the Dutch Republic's recognition of the United States as an independent government. The house which he had purchased in The Hague, Netherlands becomes the first American embassy.
1809 – An Austrian corps is defeated by the forces of the Duchy of Warsaw in the Battle of Raszyn, part of the struggles of the Fifth Coalition. On the same day the Austrian main army is defeated by a First French Empire Corps led by Louis-Nicolas Davout at the Battle of Teugen-Hausen in Bavaria, part of a four day campaign that ended in a French victory.
1810 – Venezuela achieves home rule: Vicente Emparan, Governor of the Captaincy General is removed by the people of Caracas and a junta is installed.
1839 – The Treaty of London establishes Belgium as a kingdom.
1855 – Visit of Napoleon III to Guildhall, London
1861 – American Civil War: Baltimore riot of 1861: a pro-Secession mob in Baltimore, Maryland, attacks United States Army troops marching through the city.
1892 – Charles Duryea claims to have driven the first automobile in the United States, in Springfield, Massachusetts.
1919 – Leslie Irvin of the United States makes the first successful voluntary free-fall parachute jump using a new kind of self-contained parachute.
1927 – Mae West is sentenced to 10 days in jail for obscenity for her play Sex.
1928 – The 125th and final fascicle of the Oxford English Dictionary is published.
1942 – World War II: In Poland, the Majdan-Tatarski ghetto is established, situated between the Lublin Ghetto and a Majdanek subcamp.
1943 – World War II: In Poland, German troops enter the Warsaw ghetto to round up the remaining Jews, beginning the Warsaw Ghetto Uprising.
1943 – Bicycle Day – Swiss chemist Dr. Albert Hofmann deliberately takes LSD for the first time.
1945 – Diplomatic relations between the Soviet Union and Guatemala are established.
1948 – Burma joins the United Nations.
1950 – Argentina becomes a signatory to the Buenos Aires copyright treaty.
1951 – General Douglas MacArthur retires from the military.
1954 – The Constituent Assembly of Pakistan recognises Urdu and Bengali as the national languages of Pakistan.
1955 – The German automaker Volkswagen, after six years of selling cars in the United States, founds Volkswagen of America in Englewood Cliffs, New Jersey to standardize its dealer and service network.
1956 – Actress Grace Kelly marries Prince Rainier of Monaco.
1960 – Students in South Korea hold a nationwide pro-democracy protest against president Syngman Rhee, eventually forcing him to resign.
1971 – Sierra Leone becomes a republic, and Siaka Stevens the president.
1971 – Vietnam War: Vietnam Veterans Against the War begin a five-day demonstration in Washington, D.C..
1971 – Launch of Salyut 1, the first space station.
1971 – Charles Manson is sentenced to death for conspiracy to commit the Tate/LaBianca murders.
1975 – India's first satellite Aryabhata is launched.
1984 – Advance Australia Fair is proclaimed as Australia's national anthem, and green and gold as the national colours.
1985 – FBI siege on the compound of The Covenant, The Sword, and the Arm of the Lord (CSAL) in Arkansas
1985 – U.S.S.R performs nuclear test at Eastern Kazakhstan/Semipalatinsk.

Heavy smoke pours from USS Iowa’s #2 Turret following an internal explosion
1987 – The Simpsons premieres as a short cartoon on The Tracey Ullman Show
1989 – A gun turret explodes on the USS Iowa, killing 47 sailors.
1993 – The 51-day siege of the Branch Davidian building outside Waco, Texas, USA, ends when a fire breaks out. Eighty-one people die.
1993 – South Dakota governor George Mickelson and seven others are killed when a state-owned aircraft crashes in Iowa.
1995 – Oklahoma City bombing: The Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, USA, is bombed, killing 168. That same day convicted murderer Richard Wayne Snell, who had ties to one of the bombers, Timothy McVeigh, is executed in Arkansas.
1997 – The Red River Flood of 1997 overwhelms the city of Grand Forks, North Dakota. Fire breaks out and spreads in downtown Grand Forks, but high water levels hamper efforts to reach the fire, leading to the destruction of 11 buildings.
1999 – The German Bundestag returns to Berlin, the first German parliamentary body to meet there since the Reichstag was dissolved in 1945.
2005 – Cardinal Joseph Ratzinger is elected the 265th Pope of the Catholic Church following the death of Pope John Paul II. The new Pope takes on the regnal name Benedict XVI.
2011 – Fidel Castro resigns from the Communist Party of Cuba's central committee after 45 years of holding the title.

Holidays and observances

Beginning of the Independence Movement (Venezuela)
Bicycle Day
Christian Feast Day:
Ælfheah of Canterbury
Emma of Lesum
Expeditus
George of Antioch
Pope Leo IX
April 19 (Eastern Orthodox liturgics)
Dutch-American Friendship Day (United States)
Earliest day on which First Day of Summer or Sumardagurinn fyrsti can fall, while April 25 is the latest; celebrated on the first Thursday after April 18. (Iceland)
King Mswati III's birthday (Swaziland)
Landing of the 33 (Uruguay)
National Health Day (Kiribati)
Primrose Day (United Kingdom)